3 Instrument Configuration74 Keysight U8903A User’s GuideU8903A Block DiagramA simplified U8903A block diagram is shown as follows.Figure 3-1 U8903A block diagramThe description for the U8903A block diagram is provided as follows.MeasurementAn audio signal can enter the analyzer through either the Balanced (XLR) orUnbalanced (BNC) input signal connector. The audio signal then passes throughthe AC/DC coupling circuit. If AC coupling is selected, its DC component isblocked, thus only the AC component of the signal passes through to the Rangingcircuit. However, if DC coupling is selected, the entire signal passes through to theRanging circuit.InputsBalancedUnbalancedooo AC/DCcoupling Ranging ADCLowPassfilterWeightingfilter oHighPassfilter o MeasurementalgorithmDSP software algorithmSineVariable PhaseDual Sineoooo DAC o o Gain Attenuator oooOutputsBalancedUnbalancedSquarewavegeneratoroDSP software algorithmNoise oDC oMultitone oArbitrary o
